Log merchandiser

ABSTRACT

A log merchandising apparatus includes feeding and staging feeders and a plurality of pivoting overhead truss-mounted saws. The saws are travelling saws, reversibly and independently movable along the longitudinal axis of the log by means of a rack and pinion drive and lineal bearings.

TECHNICAL FIELD OF THE INVENTION

[0001] This invention relates to a log merchandising apparatus.

BACKGROUND OF THE INVENTION

[0002] Log merchandisers process tree-length logs into shorter lengthsfor further processing. It is desirable to process the logs as quicklyas possible, with as little wasted wood as possible.

[0003] One prior art log merchandiser is disclosed in U.S. Pat. No.6,305,259, issued to Whitworth. Whitworth discloses a log processingsystem whereby logs are transported via a series of conveyor belts,through a singulator and scanner, and into a cradle assembly that holdsthe logs while pivoting adjustable saws cut them. The saws and the logcradles are both mounted on saw boxes. The entire saw box moveslaterally on wheel assemblies on floor-mounted guide rails. Each sawbox, along with its associated saw and log cradle, is positioned alongthe length of the log prior to placing the log in the log cradle.

[0004] Hydraulic cylinders move the saw boxes to their proper positions,as determined by digital probes. Accordingly, the length of thehydraulic cylinders determines the travel distance of the sawassemblies. No saw can travel farther than the length of the piston rodin the hydraulic cylinder. Even if a long hydraulic cylinder is used, noadjacent saws may move closer together than the distance determined bythe substantial width of the saw box. This limits the length of logsegments that can be cut. It also limits the length of logs that may beprocessed by the apparatus.

[0005] Other examples of travelling saws are disclosed in the prior art.U.S. Pat. No. 5,179,883 to Payr discloses a saw carriage supported onguide rails on a floor-mounted frame. A motor-driven rope pulley,supported by guide rollers attached to the frame, drives the sawcarriage laterally. Another travelling saw is described in U.S. Pat. No.4,330,019 to Murphy. In this system, each saw rests on a floor-mountedcarriage fitted with wheels that ride on rails. A pinion, rotated by amotor mounted on the saw carriage, extends out of the bottom of each sawcarriage. The pinion meshes with a rack secured to one rail to move thesaw carriage along the length of the apparatus. A similar travelling sawsystem is disclosed in U.S. Pat. No. 6,279,441 to Streblow.

[0006] In the case of each of the prior art systems described above, thesaws are mounted on relatively bulky apparatus mounted on the flooradjacent the log delivery system. This makes it difficult or dangerousfor personnel to move about the merchandiser, for example to clean ormaintain it. In addition, the rail mounted saw assemblies thatcharacterize the prior art require powerful drives to move thesignificant weight of the assemblies. This limits the accuracy and speedat which merchandising can take place.

[0007] There is therefore an advantage to moving the travelling sawassemblies in a log processing system off the floor, to a point abovethe log delivery system. One example of an overhead saw assembly is U.S.Pat. No. 5,142,955 to Hale, which discloses a travelling trim sawcarried on an aluminum and low-friction plastic carriage slidablysupported on an overhead box beam. Hale's carriage travels laterallyapproximately two feet under the control of a servomotor, which connectsto a toothed pulley engaged with an endless belt supported by anothertoothed pulley. Another overhead saw system is described in U.S. Pat.No. 4,262,572 to Flodin, wherein the saw carriage, containing one mainsaw and two horizontal saws, is supported on guide wheels that run alongan overhead track. U.S. Pat. No. 4,960,023 to Reuter discloses a thirdoverhead saw system, wherein two sliding saw carriages, each containinga plurality of saws, are suspended on an overhead guide support. Upperand lower guide rolls, or other sliding guide elements, are used tosupport the saw carriages as they move along the guide support. The sawcarriages are positioned with hydraulic cylinders fastened to the guidesupport stand.

[0008] These overhead travelling saw systems move parts of the logprocessing apparatus off the floor. However, the systems do not allowfor a plurality of independently movable saws. In addition, the beamssupporting the saws often restrict how far the saws may move in thelateral direction. Therefore, the length of logs that can be processedand the length of the cut logs are limited. This limits the efficiencyof the log processing system.

[0009] It is an object of the present invention to increase the speedand efficiency of a log merchandiser. It is a further object of thepresent invention to reduce the complexity, weight and floor spacerequired for the saw assembly and to provide a saw assembly that ishighly accurate and versatile.

[0010] These and other objects of the invention will be appreciated byreference to the summary of the invention and to the detaileddescription of the preferred embodiment that follow.

SUMMARY OF THE INVENTION

[0011] One aspect of the invention is the provision, in a logmerchandising system, of truss-mounted overhead travelling saws thatpivot downward to cut the log.

[0012] In a more specific aspect, the invention further comprises a rackand pinion drive assembly for displacing the saws laterally along thelength of the log. The displacement drive motor may be mounted directlyon the carriage, which also includes the saw motor.

[0013] In yet a further aspect, the invention comprises the use of alineal bearing assembly for facilitating lateral displacement of thesaws.

[0014] In yet another aspect, the invention comprises a log feedingapparatus to ensure that logs are fed individually, a log holdingapparatus, and overhead truss-mounted travelling saws.

[0015] The saws are mounted on an overhead truss, positioned slightlyforward of the cutting area, and pivot down toward the log in order tomake their cuts. The overhead saw assembly moves machine components offthe floor and above the log holding apparatus, reducing the amount offloor space required for the apparatus and making it easier for workersto move around the merchandiser when the saws are not in use.

[0016] The use of a rack and pinion drive assembly according to theinvention allows the entire saw system to be much smaller than prior artmerchandisers wherein each saw is mounted on an independent large boxassembly.

[0017] In one aspect, the invention is a log merchandiser comprising alog positioning stage to establish placement and orientation of a logand support a log in a stationary position in a cradle assembly having alongitudinal axis; an elongated overhead truss extending above saidcradle assembly parallel to said longitudinal axis; and a plurality ofpivoting saw assemblies mounted for lateral travel along said overheadtruss, said saw assemblies comprising a pivoting saw blade selectivelyextendible to said cradle assembly.

[0018] In a further aspect, the saw assemblies travel laterally alongsaid truss on a rack and pinion drive.

[0019] In yet a further aspect, the log merchandiser comprises linealbearing assemblies to support the saw assemblies on the overhead truss.

[0020] In a more specific aspect, each pivoting saw assembly comprises acircular saw pivotally mounted on a saw arbor; a motor to operate thesaw; and a motor to actuate said pinion so as to move the saw assemblyalong the overhead truss.

[0021] In a further aspect, the invention comprises a gear system,connected to the motor that actuates the pinion, to allow lateralmovement of said saw assembly and a lateral displacement control systemto control the lateral movement of said saw assembly.

[0022] In yet a further aspect, the invention comprises a frame tosupport said travelling saw assembly components on said truss and abearing assembly to support said frame on said truss. More specifically,the gear system is a rack and pinion gear system, comprising avertically mounted reducer, a spur rack and a spur gear engaged withsaid spur rack. The support frame comprises two vertical L-shaped platesjoined by a horizontal plate connected to the long sides of each of saidL-shaped plates, and further comprises support shelves extending fromthe short sides of each of said L-shaped plates underneath saidhorizontal plate.

[0023] The bearing assembly connects said horizontal plate to saidoverhead truss and comprises at least one linear roller bearing and atleast one linear bearing guideway which interlocks with each said linearroller bearing. In the preferred embodiment of the invention, thebearing assembly comprises four linear roller bearings, each mounted ona corner of the uppermost side of said horizontal plate. Further, thepreferred embodiment comprises two linear bearing guideways, mounted onthe lowermost side of the overhead truss, each linear bearing guidewayinterlocking with two of said linear roller bearings.

[0024] In a further aspect, the log merchandiser comprises at least onestationary circular saw mounted on the overhead truss.

[0025] In yet a further aspect, the invention may comprise a mechanismto align an end of the log with said reference line. Such mechanism maycomprise a piston pushing one end of said log.

[0026] The foregoing was intended as a broad summary only and was notintended to define the limits or requirements of the invention. Otheraspects of the invention will be appreciated by reference to thedetailed description of the preferred embodiment and to the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The preferred embodiment of the invention will be described byreference to the drawings in which:

[0028]FIG. 1 is a front view of the preferred embodiment of theinvention;

[0029]FIG. 2 is a side view of the preferred embodiment;

[0030]FIG. 3 is a side view of an overhead saw assembly according to thepreferred embodiment;

[0031]FIG. 4 is a front view of the overhead saw assembly shown in FIG.3;

[0032]FIG. 5 is a side view of the vector motor assembly, with the spurrack and pinion drive assembly and overhead truss shown in section alongline 5-5 of FIG. 4 according to a preferred embodiment;

[0033]FIG. 6 is a side view of the saw blade and pivot platform withoutthe lineal travel frame;

[0034]FIG. 7 is an enlarged view of one lineal bearing assembly thatsupports the lateral movement of the travelling saws;

[0035]FIG. 8 is a side view of the lineal travel frame, on which thetravelling saws are supported; and

[0036]FIG. 9 is a front view of the lineal travel frame of FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

[0037] In the preferred embodiment of the log merchandiser 2 of theinvention, a log is selected out of a pile with a singulating device.The log is debarked and scanned to determine defects, diameter, sweepand length. The scan enables optimization software to determine theoptimal cuts to maximize the value from the log. At the end of the scancycle, the log is carried on conveyor belts to the infeed of the logmerchandiser where it is pushed by an array of log pushers onto thebottom flight of a log feeding apparatus 4, as shown in FIG. 1.

[0038] The log feeding apparatus 4 of the log merchandiser 2 can takeseveral forms. It may be a spiral log feeder of the type disclosed inapplicant's copending U.S. patent application Ser. No. 09/997,379, whichis the embodiment shown for reference in FIG. 2. Alternatively, the logmay be fed by a quadrant log feeder of the type disclosed in U.S. Pat.No. 5,119,930, issued to Stelter, a stepped singulating and endingdevice, as disclosed in U.S. Pat. No. 5,257,688, issued to Fridlund orU.S. Pat. No. 5,174,351, issued to Lindenblatt et al, or an assemblycomprising one or more endless conveyor belts containing protrusionswhich act to carry individual logs forward and up toward the saws. Theinvention also contemplates using some of these log feeding apparatus inseries, one feeding into the next. In general, the main concern infeeding logs through the log merchandiser 2 is to ensure the logs movethrough at a consistent maximum speed, being presented to the saws forcutting at an optimal rate without overwhelming the saws. Therefore anycombination of log feeding apparatus 4 may be used. It is also possibleto eliminate the log feeding apparatus completely, if the log holdingapparatus of the next stage can properly carry out this feedingfunction.

[0039] Once a log reaches the top of the log feeding apparatus 4, itdrops over the top edge and enters the first stage of the log holdingapparatus 8. In the preferred embodiment shown in FIG. 2, the logholding apparatus is a two-stage log ladder of the type disclosed inU.S. Pat. No. 5,423,417, issued to Redekop, but any apparatus capable ofadvancing the log and properly presenting it to the saws for the cuttingcycle may be used. The main requirements for selecting a log holdingapparatus are that each log must be advanced individually and then heldsecurely at the correct elevation for the saws to descend in the cuttingcycle. Therefore, any apparatus with a secure log-holding cradle may beused to present the log to the saws for the cutting cycle. Apparatusthat contain clamps to hold the log securely may also be used, but arenot preferred, as the clamps may interfere with the cutting path of thesaws.

[0040] It may also be preferable to be able to push the log laterally,such as with a piston, in order to line up the log for an end trim cut.In the preferred embodiment, one end of the log is lined up with a fenceline as the log enters the first stage of the log holding apparatus 8.If the initial scan has determined that no cut is required to square upthe log, a piston 10 extends through the fence line to push the loglaterally such that its end is away from the “O” line, a reference pointdetermined by the cutting path of the stationary “O” saw. The firststage of the log holding apparatus 8 then advances the log into thesecond stage of the log holding apparatus 12. If the log does needtrimming, the piston 10 pushes the log such that the log is properlyaligned relative to the “O” line before the log passes on to the secondstage of the log holding apparatus 12.

[0041] The second stage of the log holding apparatus 12 presents theproperly aligned log and securely holds it in place so that the overheadsaws 14 can pivot downward to make their cuts through the log. If theend of the log is not square, it will be trimmed. The trim cut, ifrequired, will always be made at the “O” line by the “O” saw 16 (shownbest in FIG. 1). The “O” saw 16 is mounted on the underside of anoverhead truss 18, forward of the second stage of the log holdingapparatus 12. The “O” saw 16 pivots down onto the log (not shown inFIG. 1) to complete a cut and then retracts up out of the way so thesecond stage of the log holding apparatus 12 can safely eject the logsegments onto an outfeed conveyor belt. The end of the log severed bythe “O” saw 16 falls through a gap on the log cradle between the fenceline and the “O” line.

[0042] All other cuts are made with travelling overhead circular saws14, shown in more detail in FIGS. 3 and 4, which pivot into and out ofthe cutting area in the same cutting cycle. The travelling saws 14 arealso mounted on the overhead truss 18, on a linear guidance system. Thepreferred embodiment of the log merchandiser 2 consists of four or fivetravelling saws 14 plus the “O” saw 16. This embodiment is capable ofprocessing logs up to 60 feet in length. Use of more travelling saws 14and a longer overhead truss 18 would allow processing of longer logs.

[0043] The following description applies to the mounting and drivingassembly for one of the overhead travelling saws 14. Each travelling saw14 moves reversibly and independently along the length of the log on arack and pinion drive comprising a spur gear 20 which engages a rack 22mounted on the overhead truss 18. The drive assembly for the lateralmovement of each saw, best shown in FIG. 5, is mounted on the top sideof the overhead truss 18 and consists of a vector motor 24 directlyconnected to a vertically mounted reducer 26. A vector motor 24 ispreferred for this application because it offers full feedback andcontrol of the motor operation. The motor operating speed is directlylinked to the movement of the saw carriage 28 along the overhead truss18, in that the saw carriage 28 travels exactly 1.9 inches for eachrevolution of the motor. The vector motor 24 also offers electricbraking for rapid stops. The vector motor 24 will ramp up from 0 to 48inches per second (or down from 48 to 0, in the case of braking) in halfa second. Computer control of the vector motor 24, through the controlbox 30, allows precise control of overhead saw 16 travel. Once the saw14 is properly positioned for an optimal cut of the log, the vectormotor 24 stops running and the saw carriage 28 movement immediatelystops.

[0044] Referring again to FIGS. 3-5, a shaft 32 depending from thevertically mounted reducer 26 rotates a spur gear 20. The spur gear 20engages a spur rack 22, mounted on the overhead truss 18, thus drivingthe travelling saw 14 laterally along the overhead truss 18. Pilotedflange bearings 34 support the shaft 32. This type of bearing ispreferred because it allows the proper alignment of the supportingplates 38 on the top and bottom of the shaft assembly. This in turnensures the spur gear 20 and rack 22 are properly aligned and that thelineal travel frame 36 is mounted properly, reducing the chances thatthe saw carriage 28 will malfunction because of unbalanced wear onweight-bearing points. Diagonal braces 40 may be used to provide furthersupport and stability for the shaft assembly.

[0045] The lineal travel frame 36 supports the saw ladder 42, shown inFIG. 6. The saw ladder 42 consists of a circular saw 44, mounted on asaw arbor 46 and driven by motor 48, mounted rearward of the saw 44. Thediameter of the saw 44 is determined by the size of the cradles in thefinal stage of the log holding apparatus 12, and by the typical range oflog diameters that will be processed in the log merchandiser. The belt50 between the motor 48 and the saw 44 drives the saw 44. The saw 44 issupported on a pivot arm 52 which allows the saw 44 to pivot in and outof contact with the log, aided by spherical roller bearings 54 supportedon shelves 56 inside the lineal travel frame 36 (not shown in FIG. 6).In the preferred embodiment of the invention, the pivot arm 52 is a12-inch square piece of tubing. A temposonic cylinder 58 mounted in thelinear travel frame 36 controls the pivoting motion of the pivot arm 52.Control valves 60 extending below the temposonic cylinder 58 operate thecylinder 58 itself.

[0046] The linear guidance system, which connects the lineal travelframe 36 and the underside of the overhead truss 18, is shown in FIG. 5and in enlarged detail in FIG. 7. The lineal bearing guidance systemcomprises a series of linear recirculating roller bearings 62interlocked with linear bearing guideways 64, best shown in FIG. 7,which run parallel to the longitudinal axis of the log. The guideways 64depend from the overhead truss 18, while the complementary linear rollerbearings 62 protrude from the upper side of the lineal travel frame 36.The interlock between the linear roller bearing 62 and depending bearingguideway 64 securely mounts the lineal travel frame 36 on the overheadtruss 18. The lineal bearing guidance system allows smooth and securelateral movement of the overhead travelling saw 14. In the preferredembodiment of the invention, there are four linear bearings 62 for eachtravelling saw 14, arranged in a square or rectangular shape on top ofthe lineal travel frame 36, which interlock with a pair of linearbearing guideways 64 mounted on the overhead truss 18.

[0047] The lineal bearing guidance system of the present inventionallows each saw 14 to move as far as required, in order to make anoptimal cut. Each saw 14 could travel very close to its neighbor ifnecessary, for example, to cut out a small segment of the log that hasan unacceptable number of defects. Conversely, the saws 14 can travelall the way to the opposite end of the log if very few cuts arerequired. In the preferred embodiment, only four or five travelling saws14 are generally required to process logs up to 60 feet long.

[0048] The lineal travel frame 36 comprises a vertical pair of L-shapedplates 66, shown in FIG. 8, joined together on their long sides inspaced relation by a horizontal plate 68. The frame 36, shown from thefront in FIG. 9, is thus roughly three-sided, though extra supportingbrace plates 70 may be added as necessary. The short sides of thevertical plates 66 have small shelves 56, supported by gussets 72,extending into the box created by the vertical plates 66 and horizontalplate 68. These shelves 56 serve to support the spherical rollerbearings 54 (not shown), which in turn supports the entire saw ladder 42(not shown).

[0049] Once the logs are cut, the log segments are ejected onto anyoutfeed conveyor, which carry the log segments away for furtherprocessing.

[0050] It will be appreciated by those skilled in the art that othervariations to the preferred embodiment described herein may be practicedwithout departing from the scope of the invention, such scope beingproperly defined by the following claims.

1. A log merchandiser comprising: a log positioning stage to establishplacement and orientation of a log and support a log in a stationaryposition in a cradle assembly having a longitudinal axis; an elongatedoverhead truss extending above said cradle assembly parallel to saidlongitudinal axis; a plurality of pivoting saw assemblies mounted forlateral travel along said overhead truss, said saw assemblies comprisinga pivoting saw blade selectively extendible to said cradle assembly. 2.The log merchandiser of claim 1 wherein the saw assemblies travellaterally along said truss on a rack and pinion drive.
 3. The logmerchandiser of claim 2 further comprising lineal bearing assemblies tosupport the saw assemblies on the overhead truss.
 4. The logmerchandiser of claim 2, wherein each said pivoting saw assemblycomprises: a circular saw pivotally mounted on a saw arbor; a motor tooperate the saw; and a motor to actuate said pinion so as to move thesaw assembly along the overhead truss.
 5. The log merchandiser of claim4, further comprising: a gear system, connected to the motor thatactuates the pinion, to allow lateral movement of said saw assembly; anda lateral displacement control system to control the lateral movement ofsaid saw assembly.
 6. The log merchandiser of claim 5, furthercomprising: a frame to support said travelling saw assembly componentson said truss; and a bearing assembly to support said frame on saidtruss.
 7. The log merchandiser of claim 5 wherein said gear system is arack and pinion gear system, comprising: a vertically mounted reducer; aspur rack; and a spur gear engaged with said spur rack.
 8. The logmerchandiser of claim 6 wherein said frame comprises two verticalL-shaped plates joined by a horizontal plate connected to the long sidesof each of said L-shaped plates, and further comprising support shelvesextending from the short sides of each of said L-shaped platesunderneath said horizontal plate.
 9. The log merchandiser of claim 6wherein said bearing assembly connects said horizontal plate to saidoverhead truss and comprises: at least one linear roller bearing; and atleast one linear bearing guideway which interlocks with each said linearroller bearing.
 10. The log merchandiser of claim 6, wherein saidbearing assembly comprises four linear roller bearings, each mounted ona corner of the uppermost side of said horizontal plate.
 11. The logmerchandiser of claim 10, wherein two linear bearing guideways aremounted on the lowermost side of the overhead truss and each linearbearing guideway interlocks with two of said linear roller bearings. 12.The log merchandiser of claim 1, further comprising at least onestationary circular saw mounted on the overhead truss.
 13. The logmerchandiser of claim 1, further comprising a mechanism to align an endof the log with said reference line.
 14. The log merchandiser of claim 9wherein said mechanism to align said log comprises a piston pushing saidend of said log.